Well i owned a 106 gti which is near on the same as a VTS, now got a 172 phase-quick. Took them out for a blast together, my lady in the 106 and me in the 172. She is a bloody good fast driver.
There was nothing between them over all really, as said on the straights the 172 pulls on the gti, but as soon as you see a bend the gti will real the 172 right back in.
I would say straight line speed the 172 is faster but on bends the gti is faster but the breaks on the 172 are so much better than the gti.
Overall in a b road race there is nothing between them really.
Both the vts and gti are so so underestimated. I find them so much more fun to drive and would even say my old gti was a better drivers car than the 172